* Notice that the end of 2008 was unusual for the index. 2008 had the most herded and fearful stock market in recent history. If at anytime the stock market was correlated to mood, it would be then. I am not sure if a 2008 analysis can be generalized to any year but 2008.
* They have not done an analysis on 2009 or 2010, and they chose to split the analysis and pick December 2008 based on a qualitative assumption from the "stabilization of DJIA values after considerable volatility in previous months and the absence of any unusual or significant sociocultural events". December 2008 was very much in the midst of the crisis still.
* For their December "stable" data set, they only used 30 days. That is limited in sample size. There is a big pool to draw from since 2009 as the market has been relatively stable.
Right, upvoted. I read the paper and the authors are very particular in their sample selection. How could someone choose 2008 as a sample? I'd be much more impressed if they used a larger sample.
Also, some food for thought: it would be interesting to see someone testing Twitter moods as an instrumental variable for a project.
The Dow Industrial Average over the last 10 years
http://www.google.com/finance?chddm=997050&q=INDEXDJX:.D...
* Notice that the end of 2008 was unusual for the index. 2008 had the most herded and fearful stock market in recent history. If at anytime the stock market was correlated to mood, it would be then. I am not sure if a 2008 analysis can be generalized to any year but 2008.
* They have not done an analysis on 2009 or 2010, and they chose to split the analysis and pick December 2008 based on a qualitative assumption from the "stabilization of DJIA values after considerable volatility in previous months and the absence of any unusual or significant sociocultural events". December 2008 was very much in the midst of the crisis still.
* For their December "stable" data set, they only used 30 days. That is limited in sample size. There is a big pool to draw from since 2009 as the market has been relatively stable.